For example, Patent Document 1 discloses a steering control apparatus employing a steer-by-wire method. This steer-by-wire steering control apparatus mechanically separates a wheel-turning mechanism (wheel-steering mechanism) from a steering wheel by means of an engagement/disengagement mechanism and drives the wheel-turning mechanism according to the steering amount. Here, the engagement/disengagement mechanism (referred to as “disengagement mechanism” also) switches the connection/disconnection between an input shaft and an output shaft and switches the transmission/non-transmission of the power.